Treatment of quantities of water



y Sept- 12, 1933- 1 P. BoucHERoT Erm. 1,926,191

TREATMENT OF QUANTITIES OF WATER Filed Oct. 7, 1927 2 Sheets-Sheet l Figi.

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TREATMENT OFQUANTITIES OF WATER Filed Oct. '7, 1927 Q @ww www2/Mmmm SQL-AMJ Wl@ 2 Sheets-Sheet 2 Y Patented Sept. 12, 1933 -N UNITED STATES V1,926,191 y A A TREATMENT or QUANTITIES Vor" WATER Paul Bouchcrot and Georges Claude, Paris f France v Application october '1, isamserial No. 225,406, and in France October 15, 1926 Y n 'i claims. V(ci. 1835-25) The present invention relatesto improvements in the process described in the patent application of the same inventors, filed in the United States on `the 11th March1927, Ser. No. 174,616,-

for the utilization, for the purpose of power generation, of practically indefinite quantities of water, the difference of temperature between which is however very slight, and more particularly of quantities of surface water and of deep water of intertropical seas. More generally speaking, it relates to any application utilizing the generation and condensation of steam by means of the said quantities. Y

One of the essential conditions of the patent lsapplication above .referred to, consists in the direct use, in turbines, of steam supplied di- Y Yrectly by hot Water, and condensed directly by cold water, in enclosures `with a suitable vacuum.

One of the greatest diiliculties in the economical application of the process consists however in the considerable quantity of gases that may be released by the quantities ci water during their treatment in enclosures in which a much` higher vacuum has to be maintained than those which have been utilized industrially up to now. In other words, due to the v. exceedingly small pressure differences which are available inv a process of the above nature, the liberationof substantial quantities of dissolved'gases in the 3 0 vevaporating and/or condensing chambers, wouldY seriously reduce the efficiency of the process.

This difiiculty is measured by the fact that for. each kilowattehourvproduced by the steam, the quantities of gases dissolved.' are theoretically thousands of times greater than in the existing steam power houses. with .surface condensers.

The problem of the dissolved gases presents therefore here a hitherto unknown importance,-

(1) Preliminary expulsion of the gases or de` gasification, carried to a greater or less extent, from'the quantities of water before their admission into the enclosures'where vacuum. is to be maintained..y

gasification which may be used. Y

(2) Reduction of the release of the remaining gases in the said enclosures.r

(3) vExtraction of the gases released in the said enclosures by the cheapest possibley means.

In order to make the following explanation as v clear as possible, certain important parts of the apparatus used for carrying into Ypractical effect the processv forming the subject of the invention, are diagrammatically illustrated by way of example in the accompanying drawings.

Figure 1 relates to one of the methods of de- Figure 2 relates to a method of effecting the4 condensation of the steam by the cold Water during its passage lthrough the .condensing chambers. l p

Figure 3 shows a device for enablingI the gases released .to be carried away into the upper portion of the condensing chamber, this carrying" away beingeffectedA by the action of a .water y which is colder than the gases to be extracted.

Figure 4 shows a practical construction of de-V vices for the preliminary degasifying', boiling and condensing.

The hoi water and the cold water, before their sa respective admission into the boiling enclosureand into the condensing enclosure, pass through a stage or phaserof degasification which may be more yor less complete according to the conditions of operation, obtained by known means of degasication, which however are generally em` ployed for an entirely different purpose,`that is, for the purpose of avoiding oxidation in the in` terior of `the enclosures containing Water or steam.k l i This degasification is obtained by rst utilizing the reduction of, pressure during thev rising 0f the waterin the barometric columns-whichA conduct it to the'boiling and condensing'en-y closures, and by extracting the gases in one or 951 more collector chambers arranged at suitable levels of the barometric columns; the gases can then be delivered into the. atmosphere at apressure much higher than that in the condensingV chamber; in that way the work of expulsionof the fraction of the gases thus extracted, is

greatly reduced, allV the more because the proportion of steam mixed with the` gases` and always enormous in the condenser, is at the same time reduced to practically zero.

It has been'found however that this release of the dissolved gases duringthe rise` of the water in the barometric columns is far from following the decrease ofpressure; it is neces-,- sary to assist it by any suitable means. -Aswell known means assisting degasification by pressure and capable of. being used successively or simultaneously, the following may be mentioned:

Delivery into the barometric columns or into the chambers interpolated for the purpose, of a very small quantity of water saturated with gas under pressure, or simply of hot water producing in the risingwater a number of line bubbles.

mechanical means. l

Addition to` the water of solid clay, sawdust etc. f

Passage of water risingA through av reduction 0I" area which produces cvavitation,- or through masses of felt or similar substances which have a remarkable effect of accelerating the degasi-y fication, or through conduits bentin the form of elbows, half circles, circles, etc. which produce a combined action of the locall depression and of the eddying which renews the portions vof the` water exposed to the local depression. `Violent Shocks and agitation obtained for instance either by admitting into the water a very small quantity of steam under pressure, orproduced by circulatingipumpsV mounted for the purpose near the top of-the barometric'columns, or

particles, chalk,

\ Electrolysis of an iniinitesimal portion of the water, which produces the release of myriads of small ybubbles of gas, taking care by giving Athe currenta suitable sign or otherwise, to avoid any corrosion of the pipes. i

- It is possible to utilize `also the factl that the boiling of water` ina vacuum lower than its vapour tension, is a pcvferful means of Ydegasification.l When water rises in thebarometric column K (Figure 1) to the level of 'complete vacuum, a small quantity of this water will energetically boil-therein at MN; the steam carrying away the dissolved gases'into the swan neclz MB, will be condensed'aga'inby re-com'pression at B, but 'only a very small portion of the gases will" again becomeV dissolved; the rest of these gasesI collectedfat cari be extracted through T (as per example byr a vacuum pump not shown) from this lower level where there is already-a considerable absolute pressure, owing to which the work of extraction will be reduced; the extractionof the gases will also-be assisted in the portion` MN by the depression near the centre of the bend, due r'to the'change of direction.

With suitable precautions, the work of rising in the. portion AN .of the barometric column. will be practicallyrecovered in theportion MB. The liquid'freed from the gases can then be conveyed into th`e chamber C in which it is utilized.

This method of utilization of the reversibility ofthe phenomenon of evaporation, and of the nonreversibility of the gas expulsionor de'ga'si'- ication is given merely by way of. example.

rvWhatever be the means employed, this preliminary degasication will always be Ymerely a partialOne, even with sea water. ,But this very difficulty of obtaining it, hasan important ccnlr sequence, namely"v that the partly* degasiied water which passes into the boiling orl con@V densing-jenclosures,` stronglyretains the restof its gases, so' thatithe vextraction of the dissolved gases from the condensing chamber is reduced t`o a. verysmallfractionfof 'whatvmay have been feared.

It has been found that this tendency of partly'l degasiiiedwater to keepr the rest of its ga`ses ,'can`bestill further assisted.vr It'has been found for instance that, contrary tokwhat has been done upto now,,a' very satisfactory condensation can beV obtained by avoiding as far as by anyv other J Y vertically arranged below the Yrieles n. This boiling chamber.

'venting a strong heating of a thin outer film which hasnot been renewed, from becoming heated on Yaccountof the bad heat conductivity, and fromv greatly reducing the possible vacuum in the condenser. vIn these conditions the water ,of condensation gives off very little of the gases which it retained.

Figure 2 shows an example for carrying out the saidprocess: the degasified water passes through the orices n, n, n: intothe condensing chamber G under the-action `of the excess of itsu own barometric' pressure over the pressure in this chamber, tricklesV in thin layers or sheets kon cylindrical rods- T, T, T or other surfaces waterin condensing the steam which is understood to enter the chamber G through a vaporv inlet not shown, becomes gradually heated during its descent along the rods to the liquid level, but as the whole of it is aifected, this heating is Aa minimum, `as well as the pressure in the condenser. The water circulation is regulated so that this heating of the water during its trickling, should notfexceed a few degrees. The water is discharged under the surface of the sea after use, through the descending barometric column S by means Vof a pump P. The gases are tracted by a vacuum pump-not shown from the condensing'chamber through branches K', preferably near the top or" the rods TT that isto say near the admission ofthe water of condensation, in the'coldest region, so as to reduce to a minimum the enormous proportion of steam time.

It has when pushing the degasiflcation of the hot water very far, that with the same process it is even possible to avoid to a considerable extent any release of any of the gases remaining in the in fact, the quiet flow of this highly degasiiedhot water free from any gas bubbles, through inlet orifices and ovensurfaces similar to thoseofl Figure 2, may have for its result, if the lm of Water on these surfaces is very thin and if the cooling to which the hot water is submittedis very slight,that there will been also found, more particularly be no properA boiling, but `only a superficial.

the rest of the dissolved gases.

In order to increase the-utilization of the cold vaporization without any'perceptible release of 'water and thus to reduce the relative proporthree or fourv times, and the two processes couldY also be combined, the turbine driven by Athe hottest steam exnausing into the least` cold condenser, and conversely. y

kThe dissolved gases released during Ithe boiling or the condensation, are extracted at-several points of the condensing chamber, as already stated by withdrawing them near the level of admission of the cold water jets, and taking at the same time all theusual precautions as regards isothermic action of lthe compression,

clearances-etc., these `precautions being of great i importance in this case on account of the enormousl proportion of` steam to be liquefied at the beginning of the compression. The extraction apparatus, ysuch as reciprocating compressors,

ticularly by means of the ,very water used for the condensation, wholly or in part.- It will be readily understood in fact that the water which has been already used for the condensation, on rushing into .the barometricdischarge column at the lower portion of the chamber, can be utilized for mechanically carrying away the gases which collect in the lower portion on account of their greater density. It seems however advisable to complete this extraction from below by another effected at the top, with colder water.

Figure 3 shows an example `for .carrying this idea into practical effect.

T', T- are the supports for sheets of water used for condensation` which are here dat inn stead of being cylindrical, the steam arriving through chamber A from the turbine; n, n, n are the openings for cold condensation water which are preferably formed in transverse pipes close to the plates T and will ordinarily be supplied With cold degasied water from a common header which may beconnected to the same source of supplyas the pipe X,vand S theY baro.- metric column for the discharge of this water. The gases released by` the condensation water during its descent along the planes T, :TQ T g and those released by the hot 'water during the generationk of steamV and arriving' with the latter through A", collectl for the most partv in the space K2. From the. latter which has a recessed orreduced portion Y, starts a down pipe Z which at its lower portion is` in communication with the atmospheric. pressure, and ink which flows abundantly Water coming from a water supply pipe X arranged at the top. This water can be of the same origin as that escapingthrough the orifices 'lun for the condensation, that isto say it could come from the source of cold water; but as 4it is` fairly expensive to obtain, it seems preferable, after havingV utilized i itfor this extractionof the gases, toutilize it subsequently for the condensation, as it will have been heated by the condensation of the steam mixed-With the gases and by the compression of the latter, only to a negligible extent. The'water'will--thus carry away the gases by a kind of pump action which may be with continuous iiow or with intermittent flow as shown in the figure but during the time that it is thus serving will not dissolve any great amount of gas. The latter method seems prefer- As in'Figure 2, TSH

able in view of the greatvolume of gases to be extracted and can be obtained by meansv of any desired mechanism, the details of which it would be needless to describe here.

The extraction assumedghere vto havev been effected at the top, could ber effected at any other level, and this process of extraction could be moreover applied, also to the gases withdrawn either from the hotwater or from the cold water before the admission of eitherfwater into the vaporization chamber or condensation chamber,` always taking care to use for the purpose in the pumps or tromps water colder than be extracted. f

An example for carrying into practical effect the above characteristic principles ofV prelimi-V nary degasiication, .boilingV and condensation,

which is very convenient but not limitative, is shown in a very diagrammaticmannerin Figure 4. The hot water Vis taken from the surface of -thesea by means of the `barometric tube Tb; the cold water is taken in the same way through a tube T2 from a tank A in the open air, into vthebottom of which opens a tunnel connected, to the pipe which can be examined, bringing cold water from a great'depth. This arrangement makes possible free release at the atmosphericv pressure of the excess of the dissolved gases that the deep water may contain. It avoids or reduces at the same time any disturbances which variations of speed of the turbines or movements the gas to n of the platform couldV produce if the submarinel pipe were connected direct to the condensingV chambers. n

The pipes Tb and'T2, barometric columns of suitable heights, provided if necessary with regulating pumps, terminate respectively at two hori- Zontal tubular conduits B, BV built to resist the vacuum, in which the Water circulates, from the centre towards the vends and becomes degasied, for instance under the action of its agitation or of some other means such as electrolysis.v In the latter case, a conductor which may be locatedat thepoint designated E, and which is not easily corroded and cany be easily replaced,v

constitutes the anode, and the pipe itself constitute's the cathode. The length and the diameter of the pipes' Bf1L and B and the speed of water are such that, under the action of the means employed, the degasication of the water will become sufficient when the water reaches the ends of B? and B. lThe gases released under the considerable pressure obtaining in Bafand B (for instance 0.15 atmosphere) are delivered into the atmosphere by the pumps F and F'. Thence the hot water and the cold water already partly degasiiied pass reciprocally into the relatively small pipes Cf, vCl arranged in the interior and at the top of two other pipes D andDlv of much' larger size extending parallel to Ba and B `and constituting respectively the boiling and theV condensing. chambers.

`The pipes Ca, Cl are Vprovided throughout the whole of their lowerV surface, with orices through which thev water flows in jets which spread over surfaces or rods T and T1 not shown in the ligure, and produce either vaporization at D which is supposed to be a nonviolent vaporization (the hot waterV being assumed to have been already greatly degasirled 'previous-- ly, for instance owing to a higher level of the chamber B vand a greater agitation of this chamber, so as vnot to be atomized at its admission into D) or the condensation at D.V

It is also possible by arranging the pipes C', Ca near the bottom of D'and D', to replace the plates such as Ta, T (Fig.v 3), by tubes or overflow devices fed from the bottom and overiowing at the top, which in spite of an incomplete methodicity, has the great advantage of leaving the top Vof the pipes D D entirely `free from the circulation 'and withdrawal of the steam. In these pipes or other 4overflow devices losses of 'head may be produced in order to render uniform the'flow throughout the `whole lengthof the pipes.

The water trickling down all vthe rodsy or escaping from the tubes or overflow devices and collecting atjthe bottom of each pipe, flows owing to a slight slope ofthe latter, towards a barometric descent column R orvR arranged in the centre of the pipe,` in whichk a pump (notrshown) makes up forthe losses of head; The'water utilized, more particularly the cold water, is discharged below the surface of the sea so asnot to disturb thete'mperature of the surface water. 'v

Throughout the whole of their length, 'the tubular boiling and condensing chambers D D" are connected, by means of very wide vand veryA short branches H H to the admission chambers I and to the exhaust I' of theV elements of turbines Kb arranged in series on a common shaft L. Steam being'thus generatedfutilized and condensed on a very short y path or" large cross section,y the 'losses of head eral points ofthe condensing vchamber D, with are of small importance.

If an economic source `of heat were available, Aand if vit were not desired to benefit by the advantages of partial condensation of steam in the turbine, the steamvcould be superheated on itsway tothe turbine. YIt goes without saying' that precautions must be taken to'i'educe to a minimum wherever necessary, or to make remediable any corrosion byV sea water as well as deposits of any kind. Compensating pumps could be used for compensating variations ofV barometric pressure orof the tide. Y

The dissolved gases released during the'boiling or the condensation are extracted at sevthe precautions and by the means hereinbefore indicated, and are preferably compressed to the pressure of those which .the pumps F and F extract from the degasifying chambers BV and'` pressures within the general `atmospheric range, `which comprises the steps of causing the water to rise in a barometric tube connected at its n upper end to a lowv pressure chamber, so that the pressure on the water is'reduced'to substan-l tially below atmospheric, causing bubbles to form in such water to .serve as nuclei `for dissolved gases, whereby'gases are caused to come out vof solution andseparate from the water, removing liberated gases from the water to prevent such gases from building up asubstantial pressure, causing water from which gases have Vof such water. 3. Themethod ofi degasifying water, which been removed to-flow in films through a space at very low pressure,collecting water from such flow, and removing it against pressure of the atmosphere, and causing water from whichdis solved gasesv have been removed as above set forth to flow through 'a portion of said space and out through a barometric tube so as to entrain and remove from such space gases liberated from solution.

- 2. The methodof degasi'fying water, which comprises the steps'of lifting water in a baro-` metric column to approximately the vacuum' point so that the water is caused to boil, causing the watery lwhile in a closed system to ilow below such-point intoa chamber, withdrawing gases from such chamber, again causing the waterto rise by suction after leaving such chamber and removing gases released after such' second rise by thepumpaction of falling masses comprises the steps of lifting the water in a barometriccolumn to approximately thevacuum point, causing the water while` ina closed sys tem to f all below such vpoint and enter and pass throughv a vlower zone still'at pressures very substantiallybelow atmospheric, withdrawing from such lower Zone gases which have beenliberated from solution and then causing the water to rise above such lower Zone and enter a chamber maintained atza pressure low\enough to cause thewater to Ilow through said barometric tube.

4. A method asset forth in claim 3, which further comprises the step of subjecting the water to'agitation while at the pressure approxiand then causingsuch water to drop toa lowered level and to rise again to a level above said lowered level, entrapping released gases over the water atsuch lower level and removing the same.

6.7The method of -degasifying water which comprises the steps of raising water in aconduit by suction whereby the pressure is progressively reducedytreating the water during' its passage through such conduitto'stimulate the formation of gas bubbles, collecting gas of such bubbles and withdrawing same and thereafter introducing the water from which such 'gas has been withdrawn into Va chamber maintained at a lower pressure than the pressure at which such gas wasremoved and' at a pressure approximating the'vapor tension of such water.

7. The method of degasifying water, which comprises the lsteps of raising water in a conduit by suction whereby the pressure on the water is progressively reduced, inducing the formation of'gas bubbles iny thewater by means supplementary to the reduction Ain pressure, collecting gas of such bubbles and withdrawing same, and thereafter introducing the water from which such gas has been removed into a cham# ber maintained ata pressure substantially lower than the pressure at which such gas was removed. v l

f PAUL `B()UCI-IERO'I'.'y v

GEORGES CLAUDE. 

